Making a property change when an animation ends?
Actuator sensor

The actuator sensor can tell you when an actuator deactivates. In your case it can listen to your action actuator.

Remarks:


Ensure to evaluate the sensor status after the observed actuator gets activated. Otherwise you might trigger the next operation before the action actuator even started to play something.


Frame property

The action actuator allows you to setup a property to receive the currently played action frame. With a property sensor you can sense over that property to act according to the current frame. 

Remarks:


To measure the end of an animation, you need to setup the end frame twice (at the action sensor and at the action actuator)
Frames are no integer. Any equal checks will fail. You need to perform range checks.


Frame counter / Time measurement

Establish a setup that constantly increases a property by one. This enables you to trigger actuators after certain frames. 

Remarks:


There is no direct relationship between counted frames and animation
You need to be sure that the counted frame number matches what you are measuring (the duration of the animation).